1. Field of the Invention
The present invention generally relates to the art of enhancing shoe comfort and support and, more particularly, is concerned with a custom-fitted insole assembly and a method and apparatus for custom making the insole assembly.
2. Description of the Prior Art
An insole is a component of a shoe which overlies a bottom heel and sole of the shoe and on which the wearer's foot directly rests. Standard or generic insoles are produced at the shoe factory and thus are not formed specifically or customized to fit the feet of the ultimate wearer of the shoes. Most standard insoles are removable and replaceable. Although such insoles are intended to improve shoe comfort and support, they are probably as likely to lead to ill-fitted shoes which will tend to aggravate any problems already present such as due to certain destabilizing conditions exhibited by many wearers' feet.
Feet of many wearers typically are of one of two different unstable types or combinations of both. Over-pronated, floppy or flexible, foot is one unstable type. Pronation as applied to a human foot is a combination of movements of the bones and joints of the foot which results in lowering of its longitudinal arch in a way providing a normal shock absorbing mechanism. This action of the foot from a neutral position to about four degrees inwardly, helps absorb the impact of the step. Over-pronation refers to excessive inward rotation of the foot more than four degrees and particularly hinging of the foot from side to side thus the floppy appearance. The over-pronated foot appears to have a low or fallen arch, looking straight and flat on the medial side. This can lead to several problems including pressure on hips and lower back, interior or exterior knee pain, shin splints, achilles tendon problems, heel spurs and plantar faciitis, ankle pain, and bunions.
Supinated, rigid or under-pronated, foot is the other unstable type. In the supinated type, the foot predominately levers or moves back to front--heel to forefoot. Because of the lack of inward rotation, this foot-type is a poor shock absorber. Since a supinated foot is so rigid, the knees, lower back, and hips compensate to absorb the extra stress and shock the foot fails to do. The foot appears to have a high arch and a more curved appearance on the medial edge. The body's weight is placed on the forefoot and heel, more to the lateral edge of the foot than to the medial edge as in the pronated foot. When walking the foot seems to roll on the lateral edge of the foot. Because of this rigid movement, there is no weight distribution in the arch or midfoot area. Because of uneven weight distribution and lack of arch support, the supinated foot-type is prone to several injuries: meditarsal and heel problems, plantar fasciitis, heel spurs, shin splints, and knee pain on the lateral edge.
A third foot type is the desired one, commonly referred to as a stable or neutral foot. A neutral foot is one that is stable from side to side, does not tend to over rotate or excessively roll to the medial or lateral edge, and has a neutral line down the medial edge of the foot. Because the foot is naturally in a neutral position, this foot-type has the normal pronation at the end of the walking gait. The foot has an average arch height. This indicates that the foot does not have the low arch due to over-pronation, nor an extremely high arch like that of the rigid foot. The stable foot type also has a naturally even weight distribution throughout the base of the foot; equal weight on heel, lateral edge of midfoot, onto the forefoot and toes. This foot type is substantially free of apparent problems.
The objective of an insole should be to compensate for the different unstable foot types in a manner which provides a more neutral and stable base that better holds and supports the foot. Unfortunately, none of the standard or generic insoles come close to achieving this objective. The same is true of so-called "custom-fitted" insoles currently in use.
As a consequence, it is readily apparent that a need still exists for a stabilizing and neutralizing insole and a way in which to produce the same.